Surgical instrument and cartridge for use therewith

ABSTRACT

A cartridge assembly is disclosed. The cartridge assembly comprises a cartridge housing and a cartridge. The cartridge housing has a plurality of biasing members thereon. The cartridge is configured for reception at least partially within the cartridge housing. The cartridge includes a plurality of fasteners at least partially therein. The cartridge has a plurality of pockets. Each fastener is ejectable from a corresponding pocket. The cartridge has a plurality of chambers, and each chamber is adjacent a pocket and configured to store at least one fastener at least partially therein. At least one fastener is movable from the chamber to the pocket. The cartridge includes a plurality of pushers, where each pusher is configured to engage at least one corresponding fastener. At least one pusher includes at least one cam surface thereon. Each biasing member urges at least one corresponding fastener toward the corresponding pocket.

BACKGROUND

1. Technical Field

The present disclosure relates generally to instruments for surgicallyjoining tissue and, more specifically, to a surgical instrument that canbe fired more than once without being required to reload fasteners.

2. Background of Related Art

Various types of surgical instruments used to surgically join tissue areknown in the art, and are commonly used, for example, for closure oftissue or organs in transection, resection, anastomoses, for occlusionof organs in thoracic and abdominal procedures, and forelectrosurgically fusing or sealing tissue.

One example of such a surgical instrument is a surgical staplinginstrument, which may include an anvil assembly, a cartridge assemblyfor supporting an array of surgical fasteners, an approximationmechanism for approximating the cartridge and anvil assemblies, and afiring mechanism for ejecting the surgical fasteners from the cartridgeassembly.

Using a surgical instrument, it is common for a surgeon to approximatethe anvil and cartridge members. Next, the surgeon can fire theinstrument to emplace fasteners in tissue. Additionally, the surgeon mayuse the same instrument or a separate instrument to cut the tissueadjacent or between the row(s) of fasteners.

Additionally, a single use loading (“SULU”) or a disposable loading unit(“DLU”) may be attached to an elongated or endoscopic portion of asurgical stapling instrument. Such loading units allow surgical staplinginstruments to have greater versatility, for example. The loading unitsmay be configured for a single use, and/or may be configured to be usedmore than once.

Further, surgical instruments and/or loading units may include acartridge that is removable and replaceable. For example, after all ofthe fasteners in a first cartridge have been ejected, a user may removethe first cartridge and replace it with a second cartridge includingfasteners.

SUMMARY

The present disclosure relates to a cartridge assembly for use with asurgical instrument. The cartridge assembly comprises a cartridgehousing and a cartridge. The cartridge housing has a plurality ofbiasing members thereon. The cartridge is configured for reception atleast partially within the cartridge housing. The cartridge includes aplurality of fasteners at least partially therein. The cartridge has aplurality of pockets. Each fastener is ejectable from a correspondingpocket. The cartridge has a plurality of chambers therein, and eachchamber is adjacent a pocket and is configured to store at least onefastener at least partially therein. At least one fastener is movablefrom the chamber to the pocket. The cartridge includes a plurality ofpushers, where each pusher is configured to engage at least onecorresponding fastener. At least one pusher includes at least one camsurface thereon. Each biasing member urges at least one correspondingfastener toward the corresponding pocket.

The present disclosure also relates to a loading unit configured forengagement with a surgical instrument. The loading unit comprising aproximal body portion defining a longitudinal axis, a tool assemblydisposed in mechanical cooperation with the proximal body portion, and acartridge assembly disposed in mechanical cooperation with the toolassembly. The cartridge assembly comprises a cartridge housing, acartridge, and a driver. The cartridge housing has a plurality ofbiasing members thereon. The cartridge is configured for reception atleast partially within the cartridge housing and includes a plurality offasteners at least partially therein. The cartridge has a plurality ofpockets, with each fastener being ejectable from a corresponding pocket.The cartridge has a plurality of chambers therein, and each chamber isadjacent a pocket and is configured to store at least one fastener atleast partially therein. At least one fastener is movable from thechamber to the pocket. The cartridge also includes a plurality ofpushers, and each pusher is configured to engage a correspondingfastener. Each biasing member urges at least one corresponding fastenertoward the corresponding pocket. The driver is disposed in mechanicalcooperation with the cartridge assembly, and is movable substantiallyparallel to the longitudinal axis into engagement with the pushers.

The present disclosure also relates to a surgical instrument comprisinga handle assembly, a firing rod, an endoscopic portion, and a cartridgeassembly. The handle assembly includes a movable handle. The firing rodis disposed in mechanical cooperation with the movable handle. Theendoscopic portion extends distally from the handle assembly. Thecartridge assembly is disposed adjacent a distal end of the endoscopicportion and comprises a cartridge housing, a cartridge, and a pluralityof pushers. The cartridge housing has a plurality of biasing members.The cartridge is configured for reception at least partially within thecartridge housing. The cartridge includes a plurality of fasteners atleast partially therein. The cartridge has a plurality of pockets. Eachfastener is ejectable from a corresponding pocket. The cartridge has aplurality of chambers therein, and each chamber is adjacent a pocket andis configured to store at least one fastener at least partially therein.At least one fastener is movable from the chamber to the correspondingpocket. Each of the plurality of pushers is configured to engage acorresponding fastener. Each biasing member urges at least onecorresponding fastener toward the corresponding pocket. Distaladvancement of the firing rod causes sequential ejection of at leastsome of the fasteners.

The present disclosure also relates to a surgical stapling instrumentcomprising a cartridge assembly and an anvil assembly. The cartridgeassembly has a cartridge body, a plurality of pushers supporting aplurality of fasteners in the cartridge body, and a driverlongitudinally movable through the cartridge body in distal and proximaldirections. The pushers have first cam surfaces and second cam surfaces.The anvil assembly has fastener forming surfaces. The driver has anupper portion and a lower portion. The upper portion of the drivercontacts the second cam surfaces sequentially when the driver is movedin the proximal direction. The lower portion of driver contacts thefirst cam surfaces when the driver is moved in the distal direction.

BRIEF DESCRIPTION OF FIGURES

Various embodiments of the presently disclosed surgical instruments andloading units are disclosed herein with reference to the drawings,wherein:

FIG. 1A is a perspective view of a surgical instrument in accordancewith the present disclosure;

FIG. 1B is a perspective view of another surgical instrument inaccordance with the present disclosure;

FIG. 2 is a perspective view of a handle portion of the staplinginstruments of FIGS. 1A and 1B;

FIG. 3 is a perspective view of a distal portion of the handle portionof FIG. 2;

FIG. 4 is a perspective view of a loading unit of the surgicalinstruments of FIGS. 1A and 1B;

FIG. 5 is a perspective exploded view of a clamping member and driversof the surgical instruments of FIGS. 1A and 1B;

FIG. 6 is a perspective view of a portion of a cartridge assembly of thesurgical instrument of the present disclosure;

FIG. 7 is a perspective view of a portion of a cartridge housing of thecartridge assembly of FIG. 6;

FIG. 8 is a perspective view of a portion of a cartridge, a plate andfasteners of the cartridge assembly of FIG. 6;

FIG. 9 is a perspective view of a pusher and fasteners of the cartridgeassembly of FIG. 6;

FIG. 10 is a transverse cross-sectional view of a portion of thecartridge assembly of FIG. 6 including a plurality of fasteners therein;

FIG. 11 is a transverse cross-sectional view of a portion of thecartridge assembly of FIG. 6 including no fasteners therein;

FIG. 12 is a perspective view of a portion of a driver of FIG. 5;

FIG. 13 is a longitudinal cross-sectional view of a portion of thecartridge assembly of FIG. 6 in combination with a portion of a driver;and

FIG. 14 is a transverse cross-sectional view of a tool assembly,including an anvil and a cartridge channel, and including two cartridgeassemblies, two drivers, and the clamping member.

DETAILED DESCRIPTION

Embodiments of the presently disclosed surgical instrument, loading unitfor use therewith, and cartridge assembly for use therewith, aredescribed in detail with reference to the drawings, wherein likereference numerals designate corresponding elements in each of theseveral views. As is common in the art, the term “proximal” refers tothat part or component closer to the user or operator, e.g., surgeon orphysician, while the term “distal” refers to that part or componentfarther away from the user.

A surgical instrument having linear jaw members of the presentdisclosure is indicated as reference numeral 100 a in FIG. 1A. Asurgical instrument having curved jaw members of the present disclosureis indicated as reference numeral 100 b in FIG. 1B. Collectively,surgical instruments 100 a and 100 b are referred to herein as referencenumeral 100. Similarly, several features that are common to bothsurgical stapling instruments 100 a and 100 b are collectively referredto as the same reference number (e.g., handle portion 110, endoscopicportion 120, and jaw members 230).

Handle portion 110 of surgical instrument 100 is shown in FIG. 2, and anenlarged view of the distal end of handle portion 110, including adistal end of firing rod 130, is shown in FIG. 3. A single use loadingunit (“SULU”) or a disposable loading unit (“DLU”) (collectivelyreferred to as “loading unit 200”), which is mechanically engageablewith handle portion 100 is shown in FIG. 4. Loading unit 200 isattachable to endoscopic portion 120 of surgical stapling instrument100, e.g., to allow surgical instrument 100 to have greater versatility.Loading unit 200 may be configured for a single use, and/or may beconfigured to be used more than once. Alternatively, a surgicalinstrument may have a cartridge which is removable and replaceable inthe reusable jaws of the instrument.

Examples of loading units for use with a surgical stapling instrumentare disclosed in commonly-owned U.S. Pat. No. 5,752,644 to Bolanos etal., the entire contents of which are hereby incorporated by referenceherein. Further details of an endoscopic surgical stapling instrumentare described in detail in commonly-owned U.S. Pat. No. 6,953,139 toMilliman et al., the entire contents of which are hereby incorporated byreference herein.

In a surgical instrument 100 in accordance with the present disclosure,a firing rod 130 is moved distally through actuation of a movable handle132 to deploy the fasteners. For example, referring back to FIGS. 1A and1B, at least a partial actuation of movable handle 132 with respect astationary handle 134 translates firing rod 130 longitudinally, suchthat a dynamic clamping member 240, its associated bar 250, and aproximal block 260 (e.g., FIG. 5) translates longitudinally, toapproximate at least one jaw member with respect to the other. It isalso envisioned that other types of handles can be used such as, forexample, motor-driven, hydraulic, ratcheting, etc.

In the embodiment illustrated in FIG. 14, dynamic clamping member 240includes an I-shaped cross-section, the top portion of which isconfigured to engage the anvil assembly, and the bottom portion of whichis configured to engage the cartridge assembly. More particularly,engagement between the top portion of the dynamic clamping member 240and the anvil assembly causes the anvil assembly to pivot towards thecartridge assembly, e.g., to clamp tissue therebetween. Continued distaltranslation of the dynamic clamping member 240 helps maintain therelative positions of the cartridge assembly and the anvil assembly withrespect to each other.

Additionally, upon distal advancement, dynamic clamping member 240advances drivers 820 through cartridge assembly 222. As the drivers 820move distally, each driver 820 sequentially engages a plurality ofpushers, and causes the pushers to move vertically within the cartridgeassembly and eject fasteners 760 towards the anvil. The dynamic clampingmember 240 may include a cutting edge 242 on a distal face of dynamicclamping member 240 to sever the stapled tissue. Subsequent to theejection of fasteners 760, the stapled tissue is cut by the cutting edge242 of the dynamic clamping member 240.

With reference to FIG. 4, loading unit 200 of the present disclosure isshown. Loading unit 200 includes a proximal body portion 210 defining alongitudinal axis “A-A,” and a tool assembly 220 including a pair of jawmembers 230. Proximal body portion 210 is configured to removably attachto endoscopic portion 120 of surgical instrument 100. More particularly,an insertion tip 202 of loading unit 200 is linearly inserted into thedistal end of endoscopic portion 120 (FIGS. 2 and 3) of surgicalstapling instrument 100. Nubs 204 of insertion tip 202 (FIG. 4) movelinearly through slots (not shown) formed in the distal end ofendoscopic portion 120. Subsequently, loading unit 200 is rotated aboutthe longitudinal axis “A-A” such that nubs 204 move transversely throughslots (not shown) within endoscopic portion 120. Additionally, duringengagement of loading unit 200 and endoscopic portion 120, firing rod130 of handle portion 110 engages dynamic clamping member 240 of loadingunit 200 (see FIG. 5).

With reference to FIGS. 6-14, jaw members 230 of loading unit 200include an anvil assembly 600 and a cartridge channel 700. In theillustrated embodiments, cartridge channel 700 houses a first cartridgeassembly 710 a and a second cartridge assembly 710 b (collectivelyreferred to as cartridge assembly 710), and includes a track 712therebetween. Each cartridge assembly 710 includes a cartridge housing720, a cartridge or cartridge body 740, a plurality of fasteners 760, aplurality of plates 780, and a plurality of pushers 800.

With particular reference to FIG. 7, each cartridge assembly 710 a, 710b has a cartridge housing 720. One such cartridge housing 720 is shown.Cartridge housing 720 includes a plurality of biasing members 722 (e.g.,leaf springs) thereon. Biasing members 722 are flexible fingers disposedon each side of the cartridge housing 710 and that are biased towardsopposite side cartridge housing 720 (as shown in FIG. 7). Biasingmembers 722 are configured such that they are able to be against theirbias into substantial alignment with an external wall 724 of cartridgehousing 720 (see, for example, FIG. 10). As discussed below, eachbiasing member 722 is configured to bias a plate, and correspondingfasteners toward the opposite side of cartridge housing 720.

Referring now to FIGS. 8-11, cartridge or cartridge body 740, andcomponents thereof, are illustrated. Cartridge or cartridge body 740 isconfigured for reception at least partially within cartridge housing 720(FIG. 7) (e.g., a snap-fit connection) and includes a plurality ofpockets 742, and a plurality of chambers 744 (FIG. 11). Each pocket 742extends through a tissue-contacting surface 750 of cartridge body 740,and is configured to releasably store a fastener 760 that is ready to befired. Each chamber 744 is adjacent a corresponding pocket 742 and isconfigured to store fasteners 760 therein (e.g., two fasteners 760). Theconfiguration of pockets 742 and chambers 744 allows fasteners to movefrom chamber 744 to pocket 742 in response to the biasing force suppliedby biasing members 722. An internal wall 746 of cartridge body 740 isadjacent pockets 742 and resists the biasing force, such that fasteners760 do not get pushed beyond pocket 742.

With reference to FIGS. 6, 8, 10 and 11, plurality of plates 780 areshown. Plates 780 are disposed on the opposite side of chamber 744 thanpockets 742. When fasteners 760 are present in cartridge body 740 (seeFIG. 10), each plate 780 is between biasing member 722 and fastener 760.When no fasteners 760 are present in cartridge body 740 (e.g., aftereach fastener 760 has been fired; see FIG. 11), each plate 780 isbetween biasing member 722 and internal wall 746 (e.g., at leastpartially within pocket 742). Additionally, when no fasteners 760 arepresent in cartridge body 740, plates 780 block the path for advancementof pushers 800, thus preventing a user from firing/attempting to firewith an empty cartridge body 740. Plates 780 are sized to facilitatesliding within chamber 744 toward pocket 742. Additionally, and as shownin the embodiment illustrated in FIG. 8, plates 780 include a cut-outportion or indentation 782, which is sized to facilitate engagement withbiasing member 722.

With particular reference to FIGS. 9-13, a plurality of pushers 800 anda plurality of fasteners 760 are shown. Each pusher 800 includes acentral portion 802 and a pair of lateral portions 804 a, 804 b. Centralportion 802 includes a first cam surface 806 and a second cam surface808. As discussed below, each cam surface 806, 808 is configured to beengaged by a driver 820 to move pusher 800 toward and away fromtissue-contacting surface 750 of cartridge body 740. Each lateralportions 804 a, 804 b is configured to engage a fastener 760, such thatmovement of pusher 800 toward tissue-contacting surface 750 of cartridgebody 740 causes corresponding fasteners 760 to be ejected from cartridgebody 740. In the illustrated embodiments, an upper surface 805 oflateral portions 804 includes a groove thereon (see FIGS. 9 and 10) tofacilitate engagement with fastener 760.

Referring now to FIGS. 12-14 driver 820 is shown. Driver 820 is anelongated member that is configured to move longitudinally through apassage 741 (FIGS. 10 and 11) in cartridge body 740 in response toactuation of movable handle 132, for example. Driver 820 includes a slot822 therein which separates an upper portion 823 from a lower portion825. The slot 822 which extends proximally from a location adjacent adistal end thereof. Slot 822 includes a firing cam surface 824 and aretraction cam surface 826. Upon distal advancement of driver 820,firing cam surface 824 contacts first cam surface 806 of pusher 800,which causes pusher 800 to move toward tissue-contacting surface 750(FIG. 13). Further movement of the driver 820 causes sequential ejectionof the fasteners 760. Proximal movement of driver 820 causes retractioncam surface 826 to contact second cam surface 808 of pusher 800, whichcauses the pusher 800 to move away from tissue-contacting surface 750(see FIG. 13). Further such movement of the driver 820 causes sequentialretraction of the fasteners 760. Additionally, in the embodimentillustrated in FIG. 5, the driver 820 is rigidly attached to dynamicclamping member 240.

In use, actuation of movable handle 132 causes distal translation ofdynamic clamping member 240, which causes distal translation of drivers820. As drivers 820 advance distally, firing cam surfaces 824 of drivers820 contact first cam surfaces 824 of pushers 800, which causes pushers800 move toward tissue-contacting surface 750 of cartridge body 740. Asshown in FIG. 13, pushers 800 sequentially move toward tissue-contactingsurface 750 (i.e., the proximal-most pusher moves first, followed by thedistally-adjacent pusher, etc.). Movement of pushers 800 towardtissue-contacting surface 750 causes corresponding fasteners 760 to besequentially ejected from cartridge body 740. Here, after pushers 800are elevated and within slots 822 of drivers 820, pushers 800 resist theforce of corresponding biasing members 722, and thus prevent anotherfastener 760 from entering pockets 742 (i.e., the fasteners 760 remainin chambers 744). As the driver 820 is distally advancing and thefasteners 760 are being ejected from cartridge 710, a cutting element242 (FIG. 14) of dynamic clamping member 240 cuts tissue between the jawmembers 230.

After the driver 820 has been advanced a predetermined amount (e.g.,corresponding to when all fasteners 760 have been ejected), a user mayretract dynamic clamping member 240, and thus the driver 820. More thanone driver 820 is contemplated herein. Retraction of driver or drivers820 causes retracting cam surfaces 826 to contact second cam surfaces808 of pushers 800, which causes pushers 800 to sequentially move awayfrom tissue-contacting surface 750 of cartridge body 740. After pushers800 have been moved away from tissue-contacting surface 750, pushers 800no longer resist the force of corresponding biasing members 722, andthus biasing members 722 force another fastener 760 from chamber 744into pocket 742.

Once drivers 820 have been retracted a predetermined amount (e.g.,corresponding to when proximal-most fasteners 760 have been urged formchambers 744 into pockets 742), a user may repeat the process ofadvancing and retracting dynamic clamping member 240 and drivers 820 toeject another set of fasteners 760 without the need to replace cartridgechannel 700 or cartridge assemblies 710. After all of the fasteners havebeen ejected from the cartridge assemblies, the plates 780 block thedrivers from being advanced, and the clamping member 240 from beingadvanced, to prevent the firing of an empty cartridge. +

The illustrated embodiments illustrate three fasteners 760 in eachpocket 742/chamber 744, but it is envisioned and within the scope of thepresent disclosure to include more or fewer fasteners 760 therein. It isalso envisioned that at least one fastener 760 of cartridge assembly 710is a different size from other fasteners 760. For example, it isenvisioned that the inner row of fasteners (i.e., initially withinpockets 742) includes fasteners having legs of a longest length, andthat the outer row of fasteners includes fasteners having legs of ashortest length, or vice versa. Here, it is envisioned that the pushers800 are sized accordingly.

The present disclosure also includes a method of firing a set offasteners from a cartridge assembly, and then firing another set offasteners from the same cartridge assembly without the need to removeand/or replace the cartridge assembly.

The present disclosure also includes embodiments having other types ofhandles than the illustrated embodiment. For example, the presentdisclosure also includes a powered (e.g., electrically-powered,battery-powered, etc.) handle.

While the above description contains many specifics, these specificsshould not be construed as limitations on the scope of the presentdisclosure, but merely as illustrations of various embodiments thereof.Therefore, the above description should not be construed as limiting,but merely as exemplifications of various embodiments. Those skilled inthe art will envision other modifications within the scope and spirit ofthe claims appended hereto.

1. A cartridge assembly for use with a surgical instrument, thecartridge assembly comprising: a cartridge housing having a plurality ofbiasing members thereon; a cartridge configured for reception at leastpartially within the cartridge housing, the cartridge including aplurality of fasteners at least partially therein, the cartridge havinga plurality of pockets, each fastener being ejectable from acorresponding pocket, the cartridge having a plurality of chamberstherein, wherein each chamber is adjacent a pocket and is configured tostore at least one fastener at least partially therein, and wherein atleast one fastener is movable from the chamber to the pocket; and aplurality of pushers, wherein each pusher is configured to engage atleast one corresponding fastener, at least one pusher including at leastone cam surface thereon; wherein each biasing member urges at least onecorresponding fastener toward the corresponding pocket.
 2. The cartridgeassembly of claim 1, further comprising a plurality of plates, eachplate being disposed adjacent one of the biasing members.
 3. Thecartridge assembly of claim 1, wherein the biasing members are leafsprings formed within walls of the cartridge housing.
 4. The cartridgeassembly of claim 1, wherein each pusher includes a first cam surfaceand a second cam surface.
 5. The cartridge assembly of claim 4, whereinengagement between a driver and the first cam surface causes the pusherto move toward a tissue-contacting surface of the cartridge, and whereinengagement between a driver and the second cam surface causes the pusherto move away from the tissue-contacting surface of the cartridge.
 6. Aloading unit configured for engagement with a surgical instrument, theloading unit comprising: a proximal body portion defining a longitudinalaxis; a tool assembly disposed in mechanical cooperation with theproximal body portion; and a cartridge assembly disposed in mechanicalcooperation with the tool assembly, the cartridge assembly comprising: acartridge housing having a plurality of biasing members thereon; acartridge configured for reception at least partially within thecartridge housing, the cartridge including a plurality of fasteners atleast partially therein, the cartridge having a plurality of pockets,each fastener being ejectable from a corresponding pocket, the cartridgehaving a plurality of chambers therein, wherein each chamber is adjacenta pocket and is configured to store at least one fastener at leastpartially therein, and wherein at least one fastener is movable from thechamber to the pocket; a plurality of pushers, wherein each pusher isconfigured to engage a corresponding fastener; and wherein each biasingmember urges at least one corresponding fastener towards thecorresponding pocket; and a driver disposed in mechanical cooperationwith the cartridge assembly, the driver being movable substantiallyparallel to the longitudinal axis into engagement with the pushers. 7.The loading unit of claim 6, wherein each pusher includes at least onecam surface.
 8. The loading unit of claim 6, wherein each pusherincludes a first cam surface and a second cam surface.
 9. The loadingunit of claim 8, wherein the driver includes a firing cam surface and aretraction cam surface, and wherein a predetermined amount of distalmovement of the driver causes the firing cam surface to contact thefirst cam surface of each of the pushers, and wherein a predeterminedamount a proximal movement of the driver causes the retraction camsurface to contact the second cam surface of each of the pushers. 10.The loading unit of claim 9, wherein contact between the firing camsurface of the driver and the first cam surface of the pusher causes thepusher to move toward a tissue-contacting surface of the cartridge, andwherein contact between the retraction cam surface of the drive and thesecond cam surface of the pusher causes the pusher to move away from thetissue-contacting surface of the cartridge.
 11. The loading unit ofclaim 6, further comprising a plurality of plates, each plate beingdisposed adjacent one of the biasing members.
 12. The loading unit ofclaim 6, wherein the biasing members are leaf springs formed withinwalls of the cartridge housing.
 13. The loading unit of claim 6, furthercomprising a second cartridge assembly disposed in mechanicalcooperation with the tool assembly.
 14. The loading unit of claim 6,wherein each chamber stores three fasteners therein, and wherein each ofthe three fasteners is a different size from the others.
 15. The loadingunit of claim 6, wherein the driver is configured to sequentially engagethe pushers.
 16. A surgical instrument, comprising: a handle assemblyincluding a movable handle; a firing rod disposed in mechanicalcooperation with the movable handle; an endoscopic portion extendingdistally from the handle assembly; and a cartridge assembly disposedadjacent a distal end of the endoscopic portion, the cartridge assemblycomprising: a cartridge housing having a plurality of biasing members;and a cartridge configured for reception at least partially within thecartridge housing, the cartridge including a plurality of fasteners atleast partially therein, the cartridge having a plurality of pockets,each fastener being ejectable from a corresponding pocket, the cartridgehaving a plurality of chambers therein, wherein each chamber is adjacenta pocket and is configured to store at least one fastener at leastpartially therein, and wherein at least one fastener is movable from thechamber to the corresponding pocket; and a plurality of pushers, whereineach pusher is configured to engage a corresponding fastener; whereineach biasing member urges at least one corresponding fastener toward thecorresponding pocket, and wherein distal advancement of the firing rodcauses sequential ejection of at least some of the fasteners.
 17. Asurgical stapling instrument, comprising: a cartridge assembly having acartridge body, a plurality of pushers supporting a plurality offasteners in the cartridge body, and a driver longitudinally movablethrough the cartridge body in distal and proximal directions, thepushers having first cam surfaces and second cam surfaces; and an anvilassembly having fastener forming surfaces; the driver having an upperportion and a lower portion, the upper portion contacting the second camsurfaces sequentially when the driver is moved in the proximaldirection, and the lower portion of driver contacting the first camsurfaces when the driver is moved in the distal direction.